Strut structure and axial flow rotary machine including same

ABSTRACT

A strut structure includes: a hollow outer cylinder strut that extends in a direction intersecting with a rotation direction of a rotation part of an axial flow rotary machine, and is coupled to a fixed part supporting the rotation part and a base part supporting the axial flow rotary machine; and an internally hollow inner cylinder strut that is disposed inside the outer cylinder strut.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to and incorporates by reference the entire contents of Japanese Patent Application No. 2021-200418 filed in Japan on Dec. 9, 2021.

FIELD

The present disclosure relates to a strut structure and an axial flow rotary machine including the same.

BACKGROUND

As a structure for supporting a shafting of an axial flow rotary machine, there is known a structure for supporting a bearing casing and an outer peripheral casing by connecting them with a strut. For example, Patent Literature 1 discloses a structure of a strut disposed between a casing and a shaft part of a turbofan. In such a structure, typically, rigidity of the strut is high, and rigidity of a bearing and rigidity of a damper disposed on the bearing are low. In this case, vibration of the entire shafting can be damped due to a damping effect of the bearing and the damper. However, there has been the problem that, in a case in which the rigidity of the strut is low, a shaft and the bearing casing rigidly move, a vibration mode in which the strut is deformed is caused, and the vibration cannot be damped.

CITATION LIST Patent Literature

-   Patent Literature 1: Japanese Patent Application Laid-open No.     2010-112298

SUMMARY Technical Problem

In view of such a situation, an object of the present disclosure is to provide a strut structure and an axial flow rotary machine including the same with which an appropriate damping effect for vibration can be obtained.

Solution to Problem

To solve the problem described above and achieve the object, a strut structure according to the present disclosure includes: a hollow outer cylinder strut that extends in a direction intersecting with a rotation direction of a rotation part of an axial flow rotary machine, and is coupled to a fixed part for supporting the rotation part and a base part for supporting the axial flow rotary machine; and an internally hollow inner cylinder strut that is disposed inside the outer cylinder strut.

To solve the problem described above and achieve the object, a strut structure according to the present disclosure includes: an internally hollow outer cylinder strut that extends in a direction intersecting with a rotation direction of a rotation part of an axial flow rotary machine, and that is coupled to a fixed part for supporting the rotation part and a base part for supporting the axial flow rotary machine; a diaphragm part that is able to be expanded, contracted, or deformed, is disposed at an end part at which the outer cylinder strut is connected to the base part or the fixed part, and includes a damping part inside; and a disk structure that is disposed to be connected to the end part of the outer cylinder strut inside the diaphragm part.

To solve the problem described above and achieve the object, a strut structure according to the present disclosure includes: an internally hollow outer cylinder strut that extends in a direction intersecting with a rotation direction of a rotation part of an axial flow rotary machine, that is coupled to a fixed part supporting the rotation part and a base part supporting the axial flow rotary machine; a diaphragm part that is able to be expanded, contracted, or deformed, and is disposed at an end part at which the outer cylinder strut is connected to the base part or the fixed part; and a damping structure that is disposed between the diaphragm part and the base part or the fixed part, and includes a damping part and a disk structure disposed to be connected to the end part of the outer cylinder strut inside.

To solve the problem described above and achieve the object, an axial flow rotary machine according to the present disclosure includes: one of the strut structures described above; a fixed part supported by the strut structure; and a rotation part that is supported to be rotatable by the fixed part, and rotates in a direction intersecting with an axial direction of the strut structure.

Advantageous Effects of Invention

According to the present disclosure, it is possible to provide a strut structure for an axial flow rotary machine and the axial flow rotary machine including the same with which an appropriate damping effect for vibration can be obtained.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic diagram illustrating a configuration of an axial flow rotary machine.

FIG. 2 is a cross-sectional view along the line A-A of FIG. 1 .

FIG. 3 is a schematic diagram illustrating a configuration example of a strut structure according to a first embodiment.

FIG. 4A is a schematic diagram illustrating a configuration example of an outer cylinder strut of the strut structure.

FIG. 4B is a schematic diagram illustrating a configuration example of the outer cylinder strut of the strut structure.

FIG. 5 is a schematic diagram illustrating a configuration example of the strut structure.

FIG. 6 is a partial enlarged view of FIG. 5 .

FIG. 7 is a schematic diagram illustrating a first configuration example of a strut structure according to a second embodiment.

FIG. 8 is an explanatory diagram for explaining a vibration damping function of the strut structure according to the second embodiment.

FIG. 9 is a cross-sectional view along the line B-B of FIG. 8 .

FIG. 10 is a schematic diagram illustrating a second configuration example of the strut structure according to the second embodiment.

FIG. 11 is a cross-sectional view along the line C-C of FIG. 10 .

FIG. 12 is a schematic diagram illustrating a configuration example of a strut structure according to a third embodiment.

FIG. 13 is a schematic diagram illustrating a configuration example of a strut structure according to a fourth embodiment.

FIG. 14 is a schematic diagram illustrating a configuration example of a strut structure according to a fifth embodiment.

DESCRIPTION OF EMBODIMENTS

The following describes embodiments of the present disclosure in detail based on the drawings. The present disclosure is not limited to the embodiments described below.

(Strut Structure for Axial Flow Rotary Machine)

First, the following describes an axial flow rotary machine to which a strut structure according to the present disclosure is applied with reference to FIG. 1 and FIG. 2 . FIG. 1 is a schematic diagram illustrating a configuration of the axial flow rotary machine. FIG. 2 is a cross-sectional view along the line A-A of FIG. 1 . An axial flow rotary machine 100 may be a motor fan in which a fan is driven by a motor, a turbofan jet, a turbojet, a turboprop, an industrial gas turbine, or the like. As illustrated in FIG. 1 and FIG. 2 , the axial flow rotary machine 100 includes a strut structure 110, a bearing casing 120, a bearing 130, a shaft 140, a blade 150, and an outer peripheral casing 160. In the axial flow rotary machine 100, the bearing casing 120 is a fixed part of the rotary machine, and the shaft 140 and the blade 150 are rotation parts of the rotary machine. The outer peripheral casing 160 is a base part of the rotary machine.

The strut structure 110 is a structural member that is connected to the bearing casing 120 and the outer peripheral casing 160 to support them. That is, the strut structure 110 is a coupling part that couples the bearing casing 120 including a rotative structure therein to the outer peripheral casing 160 as the base part. The bearing casing 120 is a structural member that supports the bearing 130 and the shaft 140 supported by the bearing 130 inside. The bearing 130 is disposed on an outer periphery of the shaft 140 to support the shaft 140 to be rotatable with respect to the bearing casing 120. The shaft 140 is a member to which a non-driven member such as a fan is connected at one end part, which is rotated by a driving source such as a motor or a turbine. The blade 150 is a member that is connected to the shaft 140 via a disk and the like, and compresses air by being rotated following rotation of the shaft 140 to obtain propelling force. The outer peripheral casing 160 is a structural member that is connected to the strut structure 110 to be supported, covers an outer periphery of the non-driven member, and forms a flow channel for compressed air.

First Embodiment

Next, the following describes the strut structure according to a first embodiment with reference to FIG. 3 to FIG. 6 . FIG. 3 is a schematic diagram illustrating a configuration example of the strut structure according to the first embodiment. FIG. 4A is a schematic diagram illustrating a configuration example of an outer cylinder strut of the strut structure. FIG. 4B is a schematic diagram illustrating a configuration example of the outer cylinder strut of the strut structure. FIG. 5 is a schematic diagram illustrating a configuration example of the strut structure. FIG. 6 is a partial enlarged view of FIG. 5 .

As illustrated in FIG. 3 , the strut structure 110 according to the first embodiment includes an outer cylinder strut 111 and an inner cylinder strut 112.

As illustrated in FIG. 4A, the outer cylinder strut 111 (111 a) is a cylindrical member as a cylinder the cross section of which is a perfect circle. An inner part of the outer cylinder strut 111 is hollow. As illustrated in FIG. 4B as an outer cylinder strut 111 b, the outer cylinder strut 111 may be a cylindrical member as a cylinder the cross section of which is an ellipse. One end part of the outer cylinder strut 111 is connected to the bearing casing 120, and the other end part thereof is connected to the outer peripheral casing 160. The outer cylinder strut 111 supports the outer peripheral casing 160 with respect to the bearing casing 120, and supports the bearing casing 120 with respect to the outer peripheral casing 160. In the present embodiment, the outer cylinder strut 111 couples the bearing casing 120 with the outer peripheral casing 160, but objects to be coupled with each other are not specifically limited so long as the outer cylinder strut 111 is coupled to a fixed part supporting a rotation part and a base part supporting the fixed part.

The inner cylinder strut 112 is a structural member formed in a cylindrical shape the inner part of which is hollow similarly to the outer cylinder strut 111. The inner cylinder strut 112 preferably has a shape similar to that of the outer cylinder strut 111. In a case in which a cross section of the outer cylinder strut 111 b is an ellipse as illustrated in FIG. 4B, the inner cylinder strut 112 preferably has an elliptic shape. An outer diameter of the inner cylinder strut 112 is smaller than an inner diameter of the outer cylinder strut 111. Similarly to the outer cylinder strut 111, one end part of the inner cylinder strut 112 is connected to the bearing casing 120, and the other end part thereof is connected to the outer peripheral casing 160.

In the strut structure 110 according to the first embodiment, the inner cylinder strut 112 is disposed inside the outer cylinder strut 111. The outer cylinder strut 111 and the inner cylinder strut 112 are fitted to each other by clearance fit.

In a case in which the strut structure 110 is bent and deformed, sliding contact is caused between the outer cylinder strut 111 and the inner cylinder strut 112. Due to the sliding contact therebetween, frictional force functions on both of the outer cylinder strut 111 and the inner cylinder strut 112 in a direction opposite to a vibration direction. This frictional force functions as damping force for vibration of the strut structure 110. Thus, vibration of the strut structure 110 can be appropriately damped.

As illustrated in FIG. 5 and FIG. 6 as a strut structure 110 c, at least one of an inner peripheral part of an outer cylinder strut 111 c and an outer peripheral part of an inner cylinder strut 112 c may have an uneven shape. In the examples illustrated in FIG. 5 and FIG. 6 , a surface of the inner cylinder strut 112 c has an uneven shape. Alternatively, the inner peripheral surface of the outer cylinder strut 111 c may have an uneven shape, or both of the inner peripheral part of the outer cylinder strut 111 c and the outer peripheral part of the inner cylinder strut 112 c may have an uneven shape.

In the strut structure 110 c, by forming an uneven shape on the surface of the inner cylinder strut 112 c, it is possible to increase frictional force that is generated between the inner peripheral part of the outer cylinder strut 111 c and the outer peripheral part of the inner cylinder strut 112 c in a case in which the strut structure 110 c is bent and deformed. Specifically, the frictional force functions in a direction opposite to the vibration direction, so that the damping force for vibration can be increased due to the uneven shape. Thus, vibration of the strut structure 110 c can be appropriately damped.

Second Embodiment

Next, the following describes a strut structure 110 d according to a second embodiment in detail with reference to FIG. 7 . FIG. 7 is a schematic diagram illustrating a first configuration example of the strut structure according to the second embodiment.

As illustrated in FIG. 7 , the strut structure 110 according to the second embodiment includes an outer cylinder strut 111 d, an inner cylinder strut 112 d, a damping part 113, a cover part 114, and a partition part 115. The outer cylinder strut 111 d according to the second embodiment is different from that in the first embodiment in that the outer cylinder strut 111 d includes the damping part 113, the cover part 114, and the partition part 115.

One end part of the inner cylinder strut 112 d according to the second embodiment is not connected to the bearing casing 120, and the other end part thereof is connected to the outer peripheral casing 160. The inner cylinder strut 112 d is different from the inner cylinder strut 112 according to the first embodiment in that one end part of the inner cylinder strut 112 d is not fixed, that is, not connected to the bearing casing 120 in the present embodiment. The inner cylinder strut 112 d has a structure connected to the outer peripheral casing 160, but may have a structure that is connected to the bearing casing 120 but is not fixed to the outer peripheral casing 160. The inner cylinder strut may be disposed on at least one side of the strut structure to be connected, and may be disposed at any of the end parts. The same applies to the embodiments described later.

The damping part 113 is a member for damping vibration that is disposed between the outer cylinder strut 111 d and the inner cylinder strut 112 d. As the damping part 113, for example, high viscosity fluid such as lubricating oil can be used. The damping part 113 is hydraulic oil used for an oil damper, by way of example. The damping part 113 is not limited to liquid so long as the damping part 113 has a damping function, and may be an elastomer material such as rubber.

The cover part 114 covers an end part of the inner cylinder strut 112 d released toward the outer cylinder strut 111 d. When the end part of the inner cylinder strut 112 d is sealed by the cover part 114, the inner cylinder strut 112 d is caused to be in a state in which the damping part 113 is not disposed therein.

The partition part 115 is a member that partitions a space inside the outer cylinder strut 111 d. The partition part 115 is disposed on a side away from the inner cylinder strut 112 d with respect to the end part, at which the cover part 114 is disposed, of the inner cylinder strut 112 d disposed inside the outer cylinder strut 111 d. The partition part 115 partitions off the outer cylinder strut 111 d into a region in which the damping part 113 is disposed and a region in which the damping part 113 is not disposed.

FIG. 8 is an explanatory diagram for explaining a vibration damping function of the strut structure according to the second embodiment. FIG. 9 is a cross-sectional view along the line B-B of FIG. 8 . In a case in which the strut structure 110 d is bent and deformed as illustrated in FIG. 8 and FIG. 9 , the inner cylinder strut 112 d disposed inside the outer cylinder strut 111 d is displaced in the same direction as a bending direction of the outer cylinder strut 111 d. In the strut structure 110 d, when the outer cylinder strut 111 d is deformed, the damping part 113 as high viscosity fluid moves in an arrow direction illustrated in FIG. 9 in accordance with the displacement of the inner cylinder strut 112 d. At this point, the fluid moves while passing through a narrow gap, and a pressure difference is caused in the fluid. This pressure difference is increased in accordance with speed of the fluid, so that the pressure difference acts as damping force. When the gap filled with viscous fluid becomes smaller and the fluid escapes to the left and right, damping force caused by a squeeze effect is also generated.

In the strut structure 110 d, in a case in which the damping part 113 is made of an elastomer material such as rubber, and a displacement difference, that is, a relative speed is generated between the outer cylinder strut 111 d and the inner cylinder strut 112 d, the damping part 113 made of the elastomer material is elastically deformed and receives elastic force corresponding to the displacement difference, that is, the relative speed between the outer cylinder strut 111 d and the inner cylinder strut 112 d to function as damping force for vibration. Also in a case in which the damping part 113 is an elastomer, the strut structure 110 d can obtain the damping effect for vibration due to a function of the damping force.

When the strut structure 110 d has a structure in which one end part of the inner cylinder strut 112 d is opened (as a free end) within the outer cylinder strut 111 d and the cover part 114 is disposed thereon, a degree of freedom of displacement of one end part of the inner cylinder strut 112 d is increased, and by increasing the displacement difference, that is, the relative speed between the outer cylinder strut 111 d and the inner cylinder strut 112 d, the damping force can be increased.

In the strut structure 110 d, by disposing the partition part 115, it is possible to reduce capacity of the damping part 113 disposed between the outer cylinder strut 111 d and the inner cylinder strut 112 d. Due to this, weight of the strut structure 110 d can be reduced, and the strut structure 110 d can have an appropriate property as the strut structure 110 d of an axial flow rotary machine for an aircraft the increase in weight of which directly leads to deterioration of fuel efficiency.

The configuration of the strut structure 110 according to the second embodiment is not limited to the configuration illustrated in FIG. 7 , but may be configurations illustrated in FIG. 10 and FIG. 11 . FIG. 10 is a schematic diagram illustrating a second configuration example of the strut structure according to the second embodiment. FIG. 11 is a cross-sectional view along the line C-C of FIG. 10 .

As illustrated in FIG. 10 , a strut structure 110 e according to the second embodiment includes an outer cylinder strut 111 e, an inner cylinder strut 112 e, a damping part 113 e, a cover part 114 e, and an intermediate strut 116. The outer cylinder strut 111 e, the inner cylinder strut 112 e, the damping part 113 e, and the cover part 114 e are the same as those in the second embodiment, so that the description thereof will not be repeated.

The intermediate strut 116 is disposed between the inner cylinder strut 112 e and the outer cylinder strut 111 e, and formed on an outer side of the inner cylinder strut 112 e to cover the inner cylinder strut 112 e. In the second configuration example of the second embodiment, the damping part 113 e is disposed between an inner peripheral part of the intermediate strut 116 and an outer peripheral part of the inner cylinder strut 112 e.

In a case in which the inner cylinder strut 112 e is displaced, as illustrated in FIG. 11 , the strut structure 110 e receives, from the damping part 113 e, damping force in a direction opposite to a displacement direction of the inner cylinder strut 112 e, that is, a direction of relative speed with respect to the outer cylinder strut 111 e. Due to this, a damping effect for vibration can be obtained. By disposing the intermediate strut 116, the capacity of the damping part 113 e can be reduced, and the weight of the strut structure 110 e can be further reduced.

Third Embodiment

Next, the following describes a strut structure 110 f according to a third embodiment in detail with reference to FIG. 12 . FIG. 12 is a schematic diagram illustrating a configuration example of the strut structure according to the third embodiment.

As illustrated in FIG. 12 , the strut structure 110 f according to the third embodiment includes an outer cylinder strut 111 f, an inner cylinder strut 112 f, a damping part 113 f, a cover part 114 f, a partition part 115 f, and a diaphragm part 117. The outer cylinder strut 111 f, the inner cylinder strut 112 f, the damping part 113 f, the cover part 114 f, and the partition part 115 f are the same as those of the strut structure 110 d in the second embodiment, so that the description thereof will not be repeated.

The diaphragm part 117 is disposed on an end part of the outer cylinder strut 111 f, that is, an end part on the outer peripheral casing 160 side as the base part in the present embodiment. A diameter of the diaphragm part 117 is larger than that of the outer cylinder strut 111 f, and an inner part thereof is connected to the outer cylinder strut 111 f. An internal space of the diaphragm part 117 is the damping part 113 f. The diaphragm part 117 is a member that can be expanded, contracted, or deformed, that is, a member having flexibility. The outer cylinder strut 111 f is connected to the outer peripheral casing 160 via the diaphragm part 117.

In the strut structure 110 f, when the diaphragm part 117 is deformed in a case in which vibration is generated, displacement of the outer cylinder strut 111 f is increased. The inner cylinder strut 112 f is rigidly joined to the outer peripheral casing 160 as a cantilever structure. Due to this, as a displacement difference between the outer cylinder strut 111 f and the inner cylinder strut 112 f, that is, relative speed therebetween is increased in a case in which vibration is generated, damping force received from the damping part 113 f due to the relative speed therebetween largely functions, so that a structure having a large damping effect for vibration is achieved instead of low rigidity of the outer cylinder strut 111 f.

In the strut structure 110 f, it is possible to increase the displacement difference between the outer cylinder strut 111 f and the inner cylinder strut 112 f, that is, the relative speed therebetween in a case in which vibration is generated, so that the damping effect for vibration can be improved. Accordingly, vibration of the strut structure 110 f can be appropriately damped.

Fourth Embodiment

Next, the following describes a strut structure 110 g according to a fourth embodiment in detail with reference to FIG. 13 . FIG. 13 is a schematic diagram illustrating a configuration example of the strut structure according to the fourth embodiment.

As illustrated in FIG. 13 , the strut structure 110 g includes an outer cylinder strut 111 g, a damping part 113 g, a diaphragm part 117 g, a disk structure 118, and an O-ring 1180. The outer cylinder strut 111, the damping part 113 g, and the diaphragm part 117 are the same as those of the strut structure 110 f in the third embodiment, so that the description thereof will not be repeated. The strut structure 110 g according to the fourth embodiment does not include the inner cylinder strut 112, and the outer cylinder strut 111 g is connected to the outer peripheral casing 160 via the diaphragm part 117 g.

The disk structure 118 is a disk-shaped member that is disposed inside the diaphragm part 117 g, and connected to an end part of the outer cylinder strut 111 g. The O-ring 118 o is disposed between an outer periphery of the disk structure 118 and an inner periphery of the diaphragm part 117 g. The O-ring 118 o supports the disk structure 118 to be displaceable inside the diaphragm part 117 g. The damping part 113 g is filled into a region surrounded by the disk structure 118, the diaphragm part 117 g, and the O-ring 1180.

As illustrated in FIG. 13 , the disk structure 118 is disposed to be connected to the end part of the outer cylinder strut 111 g. In the strut structure 110 g, in a case in which the outer cylinder strut 111 g is displaced due to vibration, the disk structure 118 is displaced following the displacement of the outer cylinder strut 111 g. An inner part of the diaphragm part 117 is filled with the damping part 113 g, so that the damping force functions in a direction opposite to a relative speed between the disk structure 118 and the diaphragm part 117.

The strut structure 110 g includes the diaphragm part 117 and the disk structure 118, so that the strut structure 110 g can obtain the damping effect for vibration while flexibly supporting the outer cylinder strut 111 g. By increasing the diameter of the diaphragm part 117, displacement of the disk structure 118, that is, the relative speed with respect to the diaphragm part 117 is increased, so that it is possible to increase the damping force that functions in accordance with the displacement of the disk structure 118, that is, the relative speed with respect to the diaphragm part 117. Accordingly, vibration of the strut structure 110 g can be appropriately damped. Additionally, the damping part 113 g is included therein, so that the damping force can be further increased.

Fifth Embodiment

Next, the following describes a strut structure 110 h according to a fifth embodiment in detail with reference to FIG. 14 . FIG. 14 is a schematic diagram illustrating a configuration example of the strut structure according to the fifth embodiment.

As illustrated in FIG. 14 , the strut structure 110 h according to the fifth embodiment includes an outer cylinder strut 111 h, a damping part 113 h, a diaphragm part 117 h, a disk structure 118 h, and a damping structure 119. The outer cylinder strut 111 h, the damping part 113 h, the diaphragm part 117 h, and the disk structure 118 h are the same as those in the fourth embodiment, so that the description thereof will not be repeated. The fifth embodiment is different from the fourth embodiment in that the diaphragm part 117 h does not include the damping part 113 h, and the damping structure 119 is provided between the diaphragm part 117 h and an object to which the strut structure 110 h is coupled, that is, the outer peripheral casing 160 in the present embodiment.

The damping structure 119 is disposed between the diaphragm part 117 h and the outer peripheral casing 160. The damping structure 119 is a structural member including the damping part 113 h, the disk structure 118 h, and O-rings 118 o therein. The disk structure 118 h is disposed to be connected to an end part of the outer cylinder strut 111 h. The O-ring 118 o is disposed at an opening of the damping structure 119 at which the outer cylinder strut 111 h is disposed. Due to this, the damping part 113 h can be prevented from leaking to the outside of the damping structure 119. Additionally, the O-ring 118 o is also disposed between an inner periphery of the damping structure 119 and an outer periphery of the disk structure 118. Due to this, the disk structure 118 h disposed inside the damping structure 119 can be supported to be displaceable inside the damping structure 119.

In the strut structure 110 h, by separately disposing the diaphragm part 117 h that flexibly supports the outer cylinder strut 111 h and the damping structure 119 that generates a damping function, characteristics of the diaphragm part 117 h that controls rigidity and the damping structure 119 that controls damping can be separately designed. By disposing the damping part 113 h inside the damping structure 119, rigidity of a structure around the damping part 113 h is increased, so that it is possible to suppress lowering of the damping effect due to expansion, contraction, or deformation of the diaphragm part 117 h. An inner diameter of the damping structure 119 can be increased, so that the damping force can be increased by causing a high viscosity fluid to take a long way round to increase resistance. Accordingly, vibration of the strut structure 110 h can be appropriately damped.

Herein, the strut structure 110 is preferably disposed in the axial flow rotary machine. The axial flow rotary machine is preferably a motor fan. The motor fan may be, for example, an outer periphery drive motor fan and the like. The outer periphery drive motor has a structure in which a drive coil is inwardly disposed on an outer peripheral part, and a rotation coil is disposed on an outer peripheral part of a rotating body to be opposed to the drive coil. A mechanism thereof is such that, by generating a variable magnetic field in the drive coil on the outer peripheral part, an electric current is applied to the rotation coil by electromagnetic induction to obtain rotational force due to interaction with the magnetic field. The rotational force is caused to function from the outer peripheral part, so that large torque can be obtained with small rotational force. In the motor fan, torque vibration or torque ripples are generated due to a magnetic pole passing frequency of the motor. Such torque vibration causes undesired vibration in a structural member to which the motor is attached. Thus, by using the strut structure 110 according to the present disclosure as the structural member of the motor fan to which the motor is attached, vibration can be appropriately damped.

(Configurations and Effects)

The strut structure 110 according to the present disclosure includes: the hollow outer cylinder strut 111 that extends in a direction intersecting with a rotation direction of the rotation part of the axial flow rotary machine, and is coupled to the fixed part supporting the rotation part and the base part supporting the axial flow rotary machine; and the internally hollow inner cylinder strut 112 that is disposed inside the outer cylinder strut 111.

With this configuration, in a case in which vibration is applied to the strut structure 110, the outer peripheral part of the inner cylinder strut 112 disposed inside the outer cylinder strut 111 is brought into contact with the inner peripheral part of the outer cylinder strut 111 to cause frictional force, and the frictional force functions as the damping force for vibration. Accordingly, it is possible to provide the strut structure 110 with which an appropriate damping effect for vibration can be obtained.

The outer cylinder strut 111 and the inner cylinder strut 112 of the strut structure 110 according to the present disclosure are fitted to each other by clearance fit.

With this configuration, in a case in which vibration is applied to the strut structure 110, it is possible to increase a frequency at which the outer cylinder strut 111 is brought into contact with the inner cylinder strut 112. That is, it is possible to increase a frequency at which the damping force for vibration functions. Accordingly, it is possible to provide the strut structure 110 with which an appropriate damping effect for vibration can be obtained.

In the strut structure 110 according to the present disclosure, at least one of the inner peripheral part of the outer cylinder strut 111 and the outer peripheral part of the inner cylinder strut 112 has an uneven shape.

With this configuration, in a case in which vibration is applied to the strut structure 110, it is possible to increase the frictional force caused by contact between the outer peripheral part of the outer cylinder strut 111 and the inner peripheral part of the inner cylinder strut 112. The frictional force functions in a reverse direction of a sliding direction, so that the frictional force functions as the damping force for vibration. That is, with this configuration, the damping force for vibration can be increased. Accordingly, it is possible to provide the strut structure 110 with which an appropriate damping effect for vibration can be obtained.

The strut structure 110 according to the present disclosure further includes the damping part 113 for damping vibration between the inner peripheral part of the outer cylinder strut 111 and the outer peripheral part of the inner cylinder strut 112.

With this configuration, in a case in which vibration is applied to the strut structure 110, the damping force functions in a reverse direction of a vibration direction due to the damping part 113 disposed between the outer peripheral part of the outer cylinder strut 111 and the inner peripheral part of the inner cylinder strut 112. Accordingly, it is possible to provide the strut structure 110 with which an appropriate damping effect for vibration can be obtained.

The inner cylinder strut 112 d of the strut structures 110 d and 110 e according to the present disclosure has a length shorter than a total length of the outer cylinder strut 111 d, includes the cover part 114 that is disposed at an end part of the inner cylinder strut 112 d that is not connected to another portion to cover the end part of the inner cylinder strut 112 d, and includes the partition part 115 that is disposed at the end part of the outer cylinder strut 111 d on the side on which the inner cylinder strut 112 d includes the cover part 114 to partition off the outer cylinder strut 111 d into the region in which the damping part 113 d is disposed and the region in which the damping part 113 d is not disposed.

With this configuration, the length of the inner cylinder strut 112 d can be shortened and the capacity of the damping part 113 d can be reduced, so that the weight of the strut structures 110 d and 110 e can be reduced. Additionally, in a case in which vibration is applied to the strut structures 110 d and 110 e, an appropriate damping effect can be obtained. Accordingly, it is possible to provide the strut structures 110 d and 110 e with which an appropriate damping effect for vibration can be obtained.

The outer cylinder strut 111 f of the strut structure 110 f according to the present disclosure includes the diaphragm part 117 that can be expanded, contracted, or deformed, and is disposed at the end part on a side on which the damping part 113 f is disposed.

With this configuration, it is possible to increase the displacement difference between the outer cylinder strut 111 f and the inner cylinder strut 112 f, that is, the relative speed therebetween in a case in which vibration is generated, so that the damping effect for vibration can be improved. Accordingly, it is possible to provide the strut structure 110 f with which an appropriate damping effect for vibration can be obtained.

The strut structure 110 g according to the present disclosure includes: the internally hollow outer cylinder strut 111 g that extends in a direction intersecting with a rotation direction of the rotation part of the axial flow rotary machine, that is coupled to the fixed part supporting the rotation part and the base part supporting the axial flow rotary machine; the diaphragm part 117 g that can be expanded, contracted, or deformed, is disposed at the end part at which the outer cylinder strut 111 g is connected to the base part, and includes the damping part 113 g inside; and the disk structure 118 disposed to be connected to the end part of the outer cylinder strut 111 g inside the diaphragm part 117 g.

With this configuration, the damping effect for vibration can be obtained while flexibly supporting the outer cylinder strut 111 g. Additionally, by increasing the diameter of the diaphragm part 117 g, displacement of the disk structure 118, that is, the relative speed with respect to the diaphragm part 117 g is increased, so that it is possible to increase the damping force that functions in accordance with the displacement of the disk structure 118, that is, the relative speed with respect to the diaphragm part 117 g. Accordingly, it is possible to provide the strut structure 110 g with which an appropriate damping effect for vibration can be obtained.

The strut structure 110 h according to the present disclosure includes: the internally hollow outer cylinder strut 111 h that extends in a direction intersecting with a rotation direction of the rotation part of the axial flow rotary machine, that is coupled to the fixed part supporting the rotation part and the base part supporting the axial flow rotary machine; the diaphragm part 117 h that can be expanded, contracted, or deformed, and is disposed at the end part at which the outer cylinder strut 111 h is connected to the base part; and the damping structure 119 that is disposed between the diaphragm part 117 h and the base part, and includes the damping part 113 h and the disk structure 118 h disposed to be connected to the end part of the outer cylinder strut 111 h inside.

With this configuration, rigidity of a structure around the damping part 113 h is increased, so that it is possible to suppress lowering of the damping effect due to expansion, contraction, or deformation of the diaphragm part 117 h. Additionally, an inner diameter of the damping structure 119 can be increased, so that the damping force can be increased by causing the fluid to take a long way round to increase resistance. Accordingly, it is possible to provide the strut structure 110 h with which an appropriate damping effect for vibration can be obtained.

The embodiments of the present disclosure have been described above, but the embodiments are not limited thereto. The constituent elements described above encompass a constituent element easily conceivable by those skilled in the art, substantially the same constituent element, and what is called an equivalent. The constituent elements described above can be appropriately combined with each other. Furthermore, the constituent elements can be variously omitted, substituted, or modified without departing from the gist of the embodiments described above.

REFERENCE SIGNS LIST

-   -   100 Axial flow rotary machine     -   110 Strut structure     -   111 Outer cylinder strut     -   112 Inner cylinder strut     -   113 Damping part     -   114 Cover part     -   115 Partition part     -   116 Intermediate strut     -   117 Diaphragm part     -   118 Disk structure     -   119 Damping structure     -   120 Bearing casing     -   130 Bearing     -   140 Shaft     -   150 Blade     -   160 Outer peripheral casing 

1. A strut structure comprising: a hollow outer cylinder strut that extends in a direction intersecting with a rotation direction of a rotation part of an axial flow rotary machine, and is coupled to a fixed part for supporting the rotation part and a base part for supporting the axial flow rotary machine; and an internally hollow inner cylinder strut that is disposed inside the outer cylinder strut.
 2. The strut structure according to claim 1, wherein the inner cylinder strut is fitted to the outer cylinder strut by clearance fit.
 3. The strut structure according to claim 2, wherein at least one of an inner peripheral part of the outer cylinder strut and an outer peripheral part of the inner cylinder strut has an uneven shape.
 4. The strut structure according to claim 1, further comprising a damping part that damps vibration between an inner peripheral part of the outer cylinder strut and an outer peripheral part of the inner cylinder strut.
 5. The strut structure according to claim 4, wherein the inner cylinder strut has a length shorter than a total length of the outer cylinder strut, and the strut structure comprises: a cover part that is disposed at an end part of the inner cylinder strut that is not connected to another portion to cover the end part of the inner cylinder strut; and a partition part that is disposed at an end part of the outer cylinder strut on a side on which the inner cylinder strut includes the cover part to partition off the outer cylinder strut into a region in which the damping part is disposed and a region in which the damping part is not disposed.
 6. The strut structure according to claim 5, wherein the outer cylinder strut includes a diaphragm part that is able to be expanded, contracted, or deformed, and is disposed at an end part on a side on which the damping part is disposed.
 7. A strut structure comprising: an internally hollow outer cylinder strut that extends in a direction intersecting with a rotation direction of a rotation part of an axial flow rotary machine, and that is coupled to a fixed part for supporting the rotation part and a base part for supporting the axial flow rotary machine; a diaphragm part that is able to be expanded, contracted, or deformed, is disposed at an end part at which the outer cylinder strut is connected to the base part or the fixed part, and includes a damping part inside; and a disk structure that is disposed to be connected to the end part of the outer cylinder strut inside the diaphragm part.
 8. A strut structure comprising: an internally hollow outer cylinder strut that extends in a direction intersecting with a rotation direction of a rotation part of an axial flow rotary machine, that is coupled to a fixed part supporting the rotation part and a base part supporting the axial flow rotary machine; a diaphragm part that is able to be expanded, contracted, or deformed, and is disposed at an end part at which the outer cylinder strut is connected to the base part or the fixed part; and a damping structure that is disposed between the diaphragm part and the base part or the fixed part, and includes a damping part and a disk structure disposed to be connected to the end part of the outer cylinder strut inside.
 9. An axial flow rotary machine comprising: the strut structure according to claim 1; a fixed part supported by the strut structure; and a rotation part that is supported to be rotatable by the fixed part, and rotates in a direction intersecting with an axial direction of the strut structure.
 10. An axial flow rotary machine comprising: the strut structure according to claim 7; a fixed part supported by the strut structure; and a rotation part that is supported to be rotatable by the fixed part, and rotates in a direction intersecting with an axial direction of the strut structure.
 11. An axial flow rotary machine comprising: the strut structure according to claim 8; a fixed part supported by the strut structure; and a rotation part that is supported to be rotatable by the fixed part, and rotates in a direction intersecting with an axial direction of the strut structure. 